Check if string starts with a number

Question

How would I do something like this in javascript:

var s = '124sdg';
var f = 'hsdsda';
if (s.startsWith(a number)) {
   // Return true
}
if (f.startsWith(a number)) {
   // Return false
}

Answer 1

You can use a regular expression:

if (s.match(/^\d/)) {
   // Return true
}
if (f.match(/^\d/)) {
   // Return false
}

Answer 2

use a regex...

/^\d/.test(s)

which will return true or false if the first digit is a number or not